1. Field of the Invention
The present invention relates to foamed thermoplastic blends containing an aromatic polycarbonate resin and an amorphous polyamide resin. More particularly, the present invention relates to foamed thermoplastic blends of an aromatic polycarbonate resin and an amorphous polyamide derived from hexamethylene diamine, isophthalic acid and terephthalic acid.
2. Description of Related Art
Blends of polycarbonate and Nylon 6,I/T are known, see Maresca et al., U.S. Pat. No. 4,798,874, which is incorporated herein by reference. Maresca et al. discloses that the blends exhibit improved solvent resistance and substantial transparency, and that the weight ratios of amorphous polyamide to polycarbonate may be from about 1/49 to 49/1. Maresca et al. discloses that the admixture may be molded into a piece of specific dimensions or further extruded into a film or sheet product.
Polycarbonate resin foams are known, see Liberti et al., U.S. Pat. No. 4,581,382, which is incorporated herein by reference. Liberti et al. discloses various resins which can be blended with the polycarbonate.
It is desired to provide a chemically resistant polycarbonate foamed material.
Accordingly, one object of the present invention is to provide a thermoplastic foamed material exhibiting good chemical resistance.
Another object of the present invention is to provide a thermoplastic foam exhibiting chemical resistance sufficient to inhibit foam cell collapse in certain chemically harsh environments.